This invention relates to a pigmented polyolefin resin suitable for tubing and pipe service.
Although numerous dyes and pigmenting agents exist for coloring polyolefin resins, many of these agents have limited thermal stability, color fastness and exhibit compatibility problems with the base resin and various resin additives which may include antioxidants and UV stabilizers. Historically, the more stable dyes and pigments have been inorganic in nature and many contain heavy metals. For applications wherein red, orange and yellow coloring is desired, cadmium and lead-bearing dyes and pigments are routinely used. These dyes and pigments are relatively inexpensive and exhibit excellent heat stability and color fastness characteristics. However the presence of cadmium and lead in these pigments and dyes cause them to be classified as toxic chemicals under SARA Title III Section 313. Because of this, special precautions are required to minimize personnel exposure during the formulation of said dye/pigment-bearing resins and upon disposal of the resin-bearing material. These precautions are both time- and cost-intensive.